The present invention relates to a magnetic recording medium for test purposes, in particular for calibrating flying heads, comprising an inflexible substrate and at least one magnetic layer applied thereon, at least one step-shaped protrusion being provided on the surface of the magnetic layer and arranged at least partly in the recording area of the recording medium, and the protrusion consisting of hard material.
In a known method for tedting hard magnetic disks in respect to their suitability for use with flying heads, a head which is as true as possible to the service head and provided with a piezo element is allowed to fly over the entire recording area of the disk and the resulting accelerations/decelerations are measured and recorded. Because of the variability of the magnetic signals and piezo signals due to climatic conditions, dust or the test method itself, the use of original disks is not advisable. Classification of disks according to different signal amplitudes is impossible primarily because of the very different sensitivities of the flying test heads mentioned. In order to measure and electronically compensate these differences, reference disks having constant acceleration/deceleration signal values are required.
The possibility of exciting flying test heads on a simulation test stand (ie. a shaker) and measuring the system response up to about 15 kHz in comparison with sinusoidal or impulse excitation is disadvantageous since the head flight characteristics, some of which differ greatly, are not taken into account.
A magnetic recording medium of this type for testing disks or heads is already known, the magnetic layer being a phosphorus/nickel layer and a narrow step-like raised area being arranged along a radius over the recording area of the disk. The step-like raised area consists of titanium and has rounded end edges. In practical use, this disk is disadvantageous and gives in particular signals which lie in the HF (high frequency) analysis range and whose signal amplitude can be evaluated.